A software-defined network (SDN for short) is an innovative network architecture, which aims to implement network programmability and provide a good platform for innovation of a network and an application. An essence of the software-defined network is to separate network control from a physical device, and form a control hub by means of integration; therefore, the physical device has only a policy execution function and a simple data forwarding function. A current SDN solution is separating out a control plane of function network elements in the network, mainly including devices such as a switch and a router, using the control plane as a user plane device for implementation, and deploying a separated control plane device, that is, a network controller.
Centralized control is an advantage of the SDN, but also brings a problem and a challenge. If the user plane device constantly requires a decision of the network controller, a large amount of signaling is generated between the user plane device and the network controller, and a large quantity of signaling overheads greatly reduce communication efficiency of the entire network.